The transport properties of the planar rotator model on a square lattice are analysed by means of microcanonical and non-equilibrium simulations. Well below the Kosterlitz-Thouless-Berezinskii transition temperature, both approaches consistently indicate that the energy current autocorrelation displays a long-time tail decaying as t-1. This yields a thermal conductivity coefficient which diverges logarithmically with the lattice size. Conversely, conductivity is found to be finite in the high-temperature disordered phase. Simulations close to the transition temperature are instead limited by slow convergence that is presumably due to the slow kinetics of vortex pairs.
A simulation study of energy transport in the Hamiltonian XY model
Lepri S;
2005
Abstract
The transport properties of the planar rotator model on a square lattice are analysed by means of microcanonical and non-equilibrium simulations. Well below the Kosterlitz-Thouless-Berezinskii transition temperature, both approaches consistently indicate that the energy current autocorrelation displays a long-time tail decaying as t-1. This yields a thermal conductivity coefficient which diverges logarithmically with the lattice size. Conversely, conductivity is found to be finite in the high-temperature disordered phase. Simulations close to the transition temperature are instead limited by slow convergence that is presumably due to the slow kinetics of vortex pairs.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
